Window glass repair is not difficult provided you work safely and carefully. What follows are some guidelines to help you make a window glass repair on some of the more common types of windows and doors.
There are basically three types of glass repair. Repair of aluminum framed doors and windows and repair of wooden framed doors and windows. The third category would be glass repair in vinyl or other plastic dorr and window frames.
Repairing aluminum window frames, especially in aluminum storm doors is pretty straightforward. Generally these types of frames dont require any putty or adhesive. (Although some do)
Once you have removed the frame with the broken window glass, you need to lay it down on a flat work table, preferably covered in an old carpet or other non-marking surface. Aluminum storm door frames are often held together with very small sheet metal screws at all four corners.
Half the battle is getting the right screwdriver to fit those screws. You need one with a very narrow shank because you often need to push the screwdriver in through a narrow access hole to get to the screw. Other style of storm door window frame are held together with small metal clips, which must be pried loose before the frame will come apart.
Dont loose the clips !!, they will probably be impossible to purchase, so keep them in a safe place while you are replacing the glass.
The glass in a storm door window is seperated from the aluminum frame with a vinyl "glazing spline". This spline is specific to the thickness of the glass. If the old spline is in rough shape, make sure you measure the old glass thickness so you can get the right new spline.
If the window glass is only cracked, you can remove it from the frame and reassemble it on the table to get the length and width dimensions for the new piece. If the glass is completely broken, or missing, you will have to estimate how big a piece of glass to cut.
You might want to try cutting a strip of bristol board to length to see how it fits in the frame, see if the cardboard has 1/8" clearance on the top and bottom, when fit in the frame.
You can also measure the inside length and width of the frame and add in the depth of the frame on both sides. If the frame has a channel 1/2" deep, you would add 3/8" times 2 + the inside width .
It pays to be very careful measuring the glass. Its awkward to trim 1/8" off the glass if its too big, its also wasteful if the glass is cut too small and falls out of the frame when reinstalled.